An Investigation of Direct Grounding System Effect on Modeling of Lightning and Tower in Transmission Line

Lightning strikes on transmission lines can cause disruption of electrical supply. A lightning strike directly to the ground wire or the tower may result voltage rise on installed insulator at the tower. If the voltage arising on the insulator is the same or exceed the line of Critical Flashover Voltage (CFO) then there will be phenomena called back flashover. In this work, a direct conductor are installed directly from ground wire point at the top of transmission tower to ground. Several simulations are carried out to determine the conditions that may occur in a model of 150 kV transmission as to lightning strikes directly at the top of the tower, the simulation was carried out by using ATP Draw 3.8. After simulating and voltage profiles were obtained. The work was continued by analyzing the effect of the proposed additional conductor at tower to determine voltage across on the insulator that exceeds CFO. The comparison is made for the voltage profile during lightning strike for tower with and without direct conductor to ground to ensure the effectiveness of the method.